Re: plpgsql.consistent_into
От | Pavel Stehule |
---|---|
Тема | Re: plpgsql.consistent_into |
Дата | |
Msg-id | CAFj8pRCQ34VZXg-doeoDTx6FEo4qMNoERobu_KeN4KLhVexm0Q@mail.gmail.com обсуждение исходный текст |
Ответ на | Re: plpgsql.consistent_into (Gavin Flower <GavinFlower@archidevsys.co.nz>) |
Список | pgsql-hackers |
2014/1/13 Gavin Flower <GavinFlower@archidevsys.co.nz>
Possibly there should be a warning put out, whenever someone uses some behaviour that requires a GUC set to a non-default value?On 13/01/14 11:44, Florian Pflug wrote:On Jan12, 2014, at 22:37 , Pavel Stehule <pavel.stehule@gmail.com> wrote:There is GUC for variable_conflict already too. In this case I would toI must say I hate behaviour-changing GUCs with quite some passion. IMHO
enable this functionality everywhere (it is tool how to simply eliminate
some kind of strange bugs) so it needs a GUC.
We have GUC for plpgsql.variable_conflict three years and I don't know
about any problem.
they tend to cause bugs, not avoid them, in the long run. The pattern
usually is
1) Code gets written, depends on some particular set of settings
to work correctly
2) Code gets reused, with little further testing since it's supposed
to be battle-proven anyway. Settings get dropped.
3) Code blows up for those corner-cases where the setting actually
matter. Debugging is hell, because you effectively have to go
over the code line-by-line and check if it might be affected by
some GUC or another.
Only a few days ago I spent more than an hour tracking down a bug
which, as it turned out, was caused by a regex which subtly changed its
meaning depending on whether standard_conforming_strings is on or off.
Some GUCs are unavoidable - standard_conforming_strings, for example
probably still was a good idea, since the alternative would have been
to stick with the historical, non-standard behaviour forever.
But in this case, my feeling is that the trouble such a GUC may cause
out-weights the potential benefits. I'm all for having a directive like
#consistent_into (though I feel that the name could convey the
meaning better). If we *really* think that this ought to be the default
from 9.4 onward, then we should
*) Change it to always complain, except if the function explictly
specifies "#consistent_into on" or whatever.
*) Have pg_dump add that to all plpgsql functions if the server
version is < 9.4 or whatever major release this ends up in
That's all just my opinion of course.
best regards,
Florian Pflug
It is a good idea. I though about it. A worry about GUC are legitimate, but we are most static and sometimes we try to design bigger creatures, than we try to solve.
I am thinking so dump can contain a serialized GUC values, and can raises warnings when GUC are different (not only different from default).
Similar problems are with different FROM_COLAPS_LIMIT, JOIN_COLAPS_LIMIT, WORK_MEM, ...
Regards
Pavel
Pavel
Cheers,
Gavin
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